1. Field of the Invention
The present invention is directed to the field of electrical machines such as motors and generators and more specifically to the area of brush holders that are used to transfer electricity between stationary and rotating elements.
2. Description of the Prior Art
Prior art patents, such as U.S. Pat. No. 3,430,084; 3,518,475; 3,983,432; 4,389,588; and 4,371,803, illustrate the use of constant force twin coil springs within prefabricated brush boxes that each provide a guide way for a brush to move against a rotating conductor throughout its wear life. In each case, the brush box is formed with a recess in its forward end to accommodate the twin coils of the constant force spring and with a guide way having its internal dimensions configured to match and accept the brush. In each of the prior references which use the twin coil constant force spring in a brush box configuration, it is apparent that the preassembly of the brush and spring into the brush box prior to installation of the rotating conductor (such as the commutator of a motor) is complicated by the fact the springs and the brushes and springs have a tendency to fly apart, since they are biased to be disassembled in the absence of some type of spacer element positioned between the brushes.